The present invention relates to improvements in electrophoresis apparatus. More particularly it relates to improvements in apparatus for both vertical and horizontal (or so-called flat-bed) electrophoresis.
Electrophoresis, an analytical separation and analysis technique, has become an indispensible tool in science, particularly in the analysis of biological samples for enzymes, proteins, DNA, RNA and even chromosomes. Many variations of the technique have been developed over the past two decades, including slab and tube gel electrophoresis, and gradient and electrofocusing electrophoresis, and equipment for these purposes are available commercially from several suppliers. In recent years the paper and starch matrices used earlier have been largely superseded by synthetic polymer gel matrices, including polyacrylamide, and agarose gels. Polyacrylamide gels have become particularly popular, largely because of their superior resolution ability, to the extent that this type of gel has been effectively adopted as a universal standard. Because acrylamide is a synthetic compound the gel may be made up quickly and with good reproducibility, and the porosity of the gel may be varied controllably by varying the proportions of the polymer and a co-polymer, N,N'-methylene-bis-acrylamide, known popularly as "Bis".
However, analytical PAGE (the acronym generally used for polyacrylamide electrophoresis) and the commercially available apparatus for its performance suffer from a number of disadvantages. Firstly, acrylamide is claimed to be a neurotoxin and thus requires special precaution in its handling. Secondly, polyacrylamide slab gels, as well as agarose gels unlike starch slab gels, cannot readily be cut (or sliced) into thinner slabs after polymerisation has taken place and a set of samples has been run.
As a result, when a relatively large number of proteins and/or enzymes, etc. have to be analyzed for in the same sample (or set of samples) by PAGE, repetitive electrophoretic separations may have to be performed. This may not always be possible when the available sample(s) is/are very small. Moreover, complications may arise from the fact that the attainment of reproducible separations in successive runs with aliquots of the same sample(s) is not always easy.
Most of the equipment available in the trade permits the running of only a single slab gel at a time, although apparatus has become available in the last few years that permits the simultaneous running of a pair or even several slab gels, but then in a combination of separate cells. For these combinations, if the gels are connected in series, provision has to be made for high-voltage power units providing rather high potential differences, and if connected in parallel, the power units must be capable of delivering rather large currents. These high voltages and currents in turn aggravate the risk of shocks for the operator.
Since electrophoresis is a time-consuming analytical method, typically requiring several hours to complete a run, it would be advantageously simultaneously to produce a plurality of symograms (also termed electrophoretograms) from a single set of samples, preferably under identical experimental conditions.